Plate condenser having discharge elements



-K, I l I l f l y 1969 SHOICHI IWAYA ET PLA'IE CONDENSER HAVINGDISCHARGE ELEMENTS Filed Dec. 27. 1966 United States Patent U.S. Cl.317-256 Claims ABSTRACT OF THE DISCLOSURE A plate condenser havingdischarge elements comprises a plate dielectric having a thicknessselected to determine the discharge gap, a pair of electrodes in a bandformrespectively arranged above and below the dielectric in a close andflat contact with respective surfaces of the dielectric, and aninsulating layer of a thermosetting material surrounding the dielectricand electrodes over the contacting areas. Each of the band electrodes isaligned at one end of said contacting area with an end surface plane ofthe dielectric so as to constitute a discharge element in a parallelrelation with each other with its end surface exposed out of theinsulating material across the end surface of the dielectric.

This invention relates to plate condensers having discharging elements.

In a conventional condenser having a discharging gap, a part of eachcondenser electrode itself formed thinly on the dielectric of thecondenser has been used as discharging element. For example, silverelectrodes have been formed in the end part of element of a cylindricalcondenser so that, when an abnormal voltage is impressed there, adischarge may be made and thereby a characteristic of recovery may besoon obtained after the discharge. However, in such condenser, if adischarge is repeated, the thin silver electrodes near the dischargingparts will be destroyed by the discharge and will be apt to be deformedand the flashover voltage will fluctuate, so much as to be higher than20% after 800 discharges. Thus it is difiicult to obtain a uniformquality of discharge element and the life of the condenser is short. Ithas been desired to solve these defects as early as possible.

The present invention is an improvement of a conventional condenser.

An object of the present invention is to form a stable discharging partin a plate condenser having a discharging gap.

The present invention relates to the structure comprising a dielectricof a plate shape, a pair of conductors of a band shape arranged aboveand below said dielectric in a close and flat contact with respectivesurfaces of the latter so as to be a pair of electrodes, and aninsulating material layer surrounding the dielectric and electrodeportions of the conductors so as to hold them integrally.

FIG. 1A is an elevation of a plate condenser having discharging elementsaccording to the present invention.

FIG. 1B .is a side view of the same.

FIGS. 2A and 2B are views for explaining a method of manufacturing aplate condenser of the present invention.

FIG. 3 is a view showing the present invention as used.

A plate condenser having discharging elements embodying the presentinvention shall be explained in the following. In FIGS. 1A andlB showinga plate condenser having discharging elements according to the present.invention, 1 is a dielectric element made preferably of a porcelain.Such porcelain had better be strongly sintered at a high temperature andis preferably of titanium or rutile, barium titanate or anyalkaline-earth titanate, alumina, forsterite or steatite. Further, theporcelain element 1 should preferably be smooth on the surface and maybe painted on the surface with an ordinary glaze. A band conductor 3 isformed in the form of U on said element 1 as shown in FIG. 2 so as tohold the dielectric 1. After the conductor 3 having extensions 3a and 3bat its both ends is inserted into cut grooves 1-6 in a jig 12 so as tobe fitted to the jig, the element 1 held with the conductor 3 is dippedinto a bath of insulating paint 2 contained in a vessel 13. Here 7 is alimiter for regulating the length to be painted in the longitudinaldirection of the element 1. Bolts 8 are screwed into said limiter so asto adjust the position of the limiter.

When heated, the paint 2 deposited on the element 1 of the condenserwill strongly hold the conductor 3. Thus conductor 3 will be broughtinto close and flat contact with the element 1. To this end, the paint 2is preferably of a material to be solidified by heat as a vehicle. Forexample, if a mixed thermosetting epoxy-phenol resin containing ahardener is used, the conductor 3 will be able to be closed against theelement 1 at a low heating temperature. The conductor 3 is madepreferably of silverplated copper but may be made of a brass, aluminumor iron sheet. The enlarged surface parts 5 of the band conductors 3holding the dielectric element 1 between them serve as the electrodeparts of a condenser. The width and shape of the conductor parts 5 areselected in response to the required electrostatic capacitance. When thepaint 2 is set, a part 10 of the paint and bent part 11 of the conductor3 are cut off with a diamond cutter 9 or the like along the line a-bwhich corresponds to a side face plane of the element 1, so that theside face of the element 1 will be disposed between cut end edgesurfaces of the conductor 3 which is now divided into two electrodes.Thus, sectional face 4 where the side face of the element 1 andconductor edges are exposed will act as a discharge element with theconductor edges serving as a pair of discharge electrodes having astable discharging function.

Further, a part 15 not painted will be made on said element 1 by thelimiter 7. The reason for its necessity is shown in the following. Aplate condenser having discharging elements according to the presentinvention as used is shown in FIG. 3. The leading parts 13 and 14 of theconductor 3 are used as bent in a direction substantially at rightangles to the dielectric element. In such case, the unpainted part 15will have an advantage of increasing the insulating effect between theleading parts 13 and 14. The generation of coronas will be little.

As the discharging gap is determined by the thickness of the element 1,the discharging elements of the present invention can be formed to behigh in the precision. Therefore, the flashover voltage is very uniformand can be varied by varying the thickness of the element 1.

Though one element is fitted to the jig in the embodiment of thismanufacturing method, it is easy to work many at the same time. It isalso easy to make a complex cir- -cuit part. Thus two or, moredischarging elements can be formed in the same element 1. In the presentinvention, it is not necessary to specifically silverplate the element1.

The conductor 3 should be so smooth as to be easy to bring into closecontact with the element 1. The shape of the conductor part 11 in theend part of the U-shaped conductor 3 should conform to the thickness ofthe element 1.

Further, in the present invention, when the electrostatic capacitance ofthe condenser of a large value, it will not be necessary to make thewidth of the conductor 3 large. The same silver electrode as in theconventional condenser technique may be formed .in the element 1 and maybe electrically connected with the conductor 3. As the conductor 3 is inthe form of a flat plate, the radiation of heat is easy.

In such construction as in the above, when a forsterite porcelain plateof longitudinal length of 10 mm., a lateral length of 7 mm. and athickness of 0.5 mm. was used for the element 1 and a copper plate of awidth of 2.5 mm. and a thickness of 0.2 mm. was used for the conductor,a flashover voltage of 1500 v. DC was obtained.

Further, even when 5000 discharges were made, the rise of the flashovervoltage was less than 10%. Substantially no variation of theelectrostatic capacitance of the condenser was seen.

Though the discharge generated a corona once, it was soon converted to aspark discharge. The generation of coronas was very little. Even if heatwas generated by a corona loss, the heat was seen to be dissipated intothe atmosphere through the conductor 3.

Further, at not only impulse produced by a fault within the circuit butalso a high voltage close to a direct current, an alternating currentand a high freqency, a spark discharge will be easily generated and thedelay of the spark will be so little as to be presumed to be less than10 second. The voltage-time curve V-t is substantially horizontal. Thusthe electronic devices can be well protected.

The effects obtained by the plate condenser having the dischargingelements of the present invention as described above can endure manydischarges and give stable electronic circuits. Said condenser is veryeasy to make and can protect electronic devices while keeping the actionof a condenser. Further, in the present invention, the flashover voltageis stable, complex parts can be easily made, the condenser can be madesmall and, as the conductor 3 can be made parallel in packing andtransportation, it is easy to handle. Thus, the condenser of the presentinvention has a technical substance far more advanced than of anyconventional condenser and its industrial value is large.

While there has been described in connection with the preferredembodiment of this invention, it will be obvious to those skilled in theart that various changes and modifications may be made therein Withoutdeparting from the invention, and it is aimed, therefore, to cover inthe appended claims all such changes and modifications as fall withinthe true spirit and scope of the invention.

What is claimed is:

1. In a condenser structure of the plate type, the combinationcomprising a flat plate made from a dielectricmaterial, a pair of bandelectrodes applied to and in contact with opposite side faces of saiddielectric plate, one end of each of said electrodes terminating at anend face of said dielectric plate to establish a discharge gap betweensaid electrode ends across the said end face, the other ends of saidelectrodes extending beyond the opposite end face of said dielectricplate, and an insulating layer applied to the opposite side faces ofsaid dielectric plate and over the appertaining portions of said bandelectrodes in contact therewith to rigidly secure said band electrodesin place on said dielectric plate.

2. A condenser structure as defined in claim 1 wherein the opposite sidefaces of said dielectric plate at the regions adjacent the extendedportions of said band electrodes do not include said insulating layer.

3. A condenser structure as defined in claim 1 wherein the width of saidband electrodes is less than the width of said dielectric plate.

4. A condenser structure as defined in claim 1 Wherein those portions ofsaid band electrodes which are covered by said insulating layer arewider than the portions which extend beyond the dielectric plate.

5. A condenser structure as defined in claim 1 wherein said insulatinglayer is a hardened thermosetting resin material.

References Cited UNITED STATES PATENTS 1,768,430 6/1930 Van Deventer31761 X 2,764,718 9/1956 Peck 3l7261 X 2,940,035 6/1960 Lefkowitz317-256 X 3,087,093 4/1963 Bourgerie 317-256 X 3,130,475 4/1964 Reith3l7261 X OTHER REFERENCES German printed application to Nordd No.1,134,164, published Aug. 2, 1962.

LEWIS H. MYERS, Primary Examiner E. A. GOLDBERG, Assistant Examiner US.Cl. X.R.

